1. Field of the Invention
The present invention relates to a stacked solid electrolytic capacitor, in particular, to a lamellar stacked solid electrolytic capacitor.
2. Description of Related Art
Various applications of capacitors include home appliances, computer motherboards and peripherals, power supplies, communication products and automobiles. The capacitors are mainly used to provide filtering, bypassing, rectifying, coupling, blocking or transforming function, which play an important role in the electric and electronic products. There are different capacitors, such as aluminum electrolytic capacitors, tantalum electrolytic capacitors or laminated ceramic capacitors, in different utilization.
A typical aluminum electrolytic capacitor includes an anode foil and a cathode foil processed by surface-enlargement and/or formation treatments. The surface-enlargement treatment is performed by etching a high purity aluminum foil to increase its surface area so that a high capacitor can be obtained to achieve miniaturized electrolytic capacitor. The anode aluminum foil is then subjected to the formation treatment to form a dielectric surface film. A thickness of the dielectric film is related to a supply voltage of the electrolytic capacitor. Normally the cathode foil will be subjected to the formation treatment, too. However, if no formation treatment on the cathode foil, an oxide film layer will be still farmed on the surface when exposed in the air. After cutting to a specific size according to design spec., a laminate made up of the anode foil, the cathode foil which is opposed to the dielectric film of the anode foil and has etched surfaces, and a separator interposed between the anode and cathode foils, is wound to provide an element. The wound element does not have any electric characteristic of the electrolytic capacitor yet until completely dipped in an electrolytic solution for driving and housed in a metallic sheathed package in cylindrical form with a closed-end equipping a releaser. Furthermore, a sealing member made of elastic rubber is inserted into an open-end section of the sheathed package, and the open-end section of the sheathed package is sealed by drawing, whereby an aluminum electrolytic capacitor is constituted.
In fact, the electrolytic capacitor utilizes the mobility of ions in the electrolytic solution to obtain an electric circuit; therefore, the electrical conductivity of the electrolytic solution is an important factor for deciding performance of the electrolytic capacitor. Such that, it is an issue for how to promote the electrical conductivity of the electrolytic solution to maintain the electrolytic capacitor with high-temperature stability on the solution, the aluminum foils, the separator and etc., especially the stability of the solution and the aluminum foils. A typical electrolytic solution for a conventional electrolytic capacitor, especially for those electrolytic capacitors work on a supply voltage under 100V, includes water, organic solvent, organic acid, inorganic acid and some special additives mixed in different proportions.
Moreover, because solid electrolytic capacitor has the advantages of small size, large capacitor and good frequency characteristic, it can be used as a decoupling element in the power circuit of a central processing unit (CPU). In general, a plurality of capacitor elements is stacked together to form a solid electrolytic capacitor with a high capacitor. In addition, the solid electrolytic capacitor of the prior art includes a plurality of capacitor elements and a lead frame. Each capacitor element includes an anode part, a cathode part and an insulating part. The insulating part electrically insulates the anode part and the cathode part from each other. More specifically, the cathode parts of the capacitor elements are stacked over one another. Furthermore, conductive layers are disposed between adjacent capacitor elements so that the capacitor elements are electrically connected to one another.
Furthermore, the winding capacitor includes a capacitor element, a packaging material, and a sealing material. The capacitor element has an anode foil coupled to an anode terminal, a cathode foil coupled to a cathode terminal, a separator, and an electrolyte layer. The anode foil, the cathode foil and the separator are rolled together. The separator is between the anode foil and the cathode foil. The electrolyte layer is formed between the anode foil and the cathode foil. The packaging material has an opening and packages the capacitor element. The sealing material has a through hole where the anode terminal and the cathode terminal pass through and seals the opening of the packaging material. A given space is provided between the sealing material and the capacitor element. A stopper for securing the space is provided on at least one of the anode terminal and the cathode terminal.